brew-your-own-unibus boards?

From: Christian Fandt <>
Date: Mon Jan 19 21:26:32 2004

Upon the date 04:24 PM 1/19/04 -0500, Brad Parker said something like:

>I have half a mind to look over the "IDE for Soviet unibus" zip file I
>found and make my own uniboard board with a modern day CPLD and IDE
>How crazy is that?

Well, not crazy in my book. I'm much more a hardware man, not so much
software, in interests - similar to Tony D. and a few others here. This is
a solution.

>I have 4-8 layer PCB's fabricated regularly and have a reasonable CAD
>setup to do that, so design, layout & fabrication is not a problem, nor
>is TTL design (heh, especially at unibus speeds :-) And I write VHDL for
>CPLD's all the time and program them.
>Seems like a 4 layer board with gold fingers would work - the few boards
>I've handled seemed pretty thick, however. I'm guessing the thickness
>needs to be correct.

I have not noticed any oddball thickness on any of the Unibus boards I
have. I can mike a bunch to get a mean thickness, but I suspect the
dimension would be right in the range typically found on any other computer
PCB (what was that? 60 thousandths or ?? Been too long to recall now . . .)
The specs from the original vendors of the card edge connectors in DEC and
compatible systems will of course drive the board thickness tolerance.

>I have not (yet) looked at a unibus card schematic - would be it hard to
>create a bus master IDE interface?

The bus driver/receiver rules need to be adhered to, but I don't feel it's
beyond your capability it seems.

>Is a unibus controller a relatively straight forward TTL design ?
>I should probably ask on the PUP list also, but I thougth I'd see if
>anyone here has opinions.
>And, if I did manage to create a realiable IDE interface, would anyone
>else want one?


Also Qbus would be of very strong interest too. I have at least two Unibus
and four or perhaps five Qbus machines which would be targets of an IDE

>(I realize cost would be the overriding factor - believe it or not on
>small runs like I do the PCB is by far the most expensive part)

Well, cost should be somewhat of a factor for most of us. The vast majority
who would use the subject Unibus/Qbus interfaces are hobbyists and, like
me, have more than one system but decidedly limited funds. IMHO, very few,
if any, commercial users would be potential customers as they may prefer to
spend the buck to find exact replacement drives/controllers and not risk
complications from some untried mass storage hardware system.

A stable design insensitive to all potential OS's which could be used (and
vice versa) will be quite welcome in this house. Bring it on.

Regards, Chris

Christian Fandt, Electronic/Electrical Historian
Jamestown, NY USA
         Member of Antique Wireless Association
Received on Mon Jan 19 2004 - 21:26:32 GMT

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